Figure 9
Left: The first ten eigenvectors 
extracted from the Summer 2014 muon tomography data. All the eigenvectors should be centred but here we added an increasing offset so that the trends do not superimpose on each other. To construct them each observation axis was previously smoothed using a 30 days large Hamming moving window. Right: Graphical representation of the four first eigenvector contributions to the measured signal. Each box corresponds to an independent observation axis i and the associated color relates to 
(j going from 1 to 4). C0 is a scaling constant. The black solid curve delimits the interface between the volcanic dome and the sky. The red triangles refer to the different active zones visible at the surface of the dome azimuths (Fig. 1).
